"effective and is quite common in politics. This type of argument attempts to undermine a speaker or writer’s ethos. "

Despite this being a logical fallacy, it's interesting to see how it can be effective because it undermines persuasion tactics. This tells me that logical fallacy doesn't always mean ineffective.

Interesting to see the ties between Ethos and something so subliminal such as a white coat as the white coat relates to medical profession. This shows me that these persuasion tactics are not just limited to something more direct, and can be subliminal instead.

Ethos: Literal meaning trust.